An adapted version of The Beatles' album sleeve for Sgt. Pepper's Lonely Hearts Club Band has been named the world's most valuable record cover.Sir Peter Blake created the original artwork for the album but it was modified for a limited edition version in 1967, which included the faces of bosses at their U.S. record label Capitol Records instead of the bandmembers' faces. It is thought only 100 copies of the adapted version were released - and now the sleeves have been valued at $112,000 (£70,000). Other albums by the Fab Four also included in the top 10 Record Collector survey include 1968's self-titled disc - known as The White Album - and their 1966 U.S. compilation Yesterday and Today.AC DC's 12 Of The Best and Hank Mobley's self-titled record were also named in the top 10 most expensive record sleeves of all time.